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-rw-r--r--arch/x86/net/bpf_jit_comp.c152
1 files changed, 98 insertions, 54 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 8cd23d8309bf..fb99d976ad6e 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -198,6 +198,8 @@ struct jit_context {
/* Maximum number of bytes emitted while JITing one eBPF insn */
#define BPF_MAX_INSN_SIZE 128
#define BPF_INSN_SAFETY 64
+/* number of bytes emit_call() needs to generate call instruction */
+#define X86_CALL_SIZE 5
#define PROLOGUE_SIZE 20
@@ -390,6 +392,99 @@ static void emit_mov_reg(u8 **pprog, bool is64, u32 dst_reg, u32 src_reg)
*pprog = prog;
}
+/* LDX: dst_reg = *(u8*)(src_reg + off) */
+static void emit_ldx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+
+ switch (size) {
+ case BPF_B:
+ /* Emit 'movzx rax, byte ptr [rax + off]' */
+ EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
+ break;
+ case BPF_H:
+ /* Emit 'movzx rax, word ptr [rax + off]' */
+ EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
+ break;
+ case BPF_W:
+ /* Emit 'mov eax, dword ptr [rax+0x14]' */
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
+ else
+ EMIT1(0x8B);
+ break;
+ case BPF_DW:
+ /* Emit 'mov rax, qword ptr [rax+0x14]' */
+ EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
+ break;
+ }
+ /*
+ * If insn->off == 0 we can save one extra byte, but
+ * special case of x86 R13 which always needs an offset
+ * is not worth the hassle
+ */
+ if (is_imm8(off))
+ EMIT2(add_2reg(0x40, src_reg, dst_reg), off);
+ else
+ EMIT1_off32(add_2reg(0x80, src_reg, dst_reg), off);
+ *pprog = prog;
+}
+
+/* STX: *(u8*)(dst_reg + off) = src_reg */
+static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+
+ switch (size) {
+ case BPF_B:
+ /* Emit 'mov byte ptr [rax + off], al' */
+ if (is_ereg(dst_reg) || is_ereg(src_reg) ||
+ /* We have to add extra byte for x86 SIL, DIL regs */
+ src_reg == BPF_REG_1 || src_reg == BPF_REG_2)
+ EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
+ else
+ EMIT1(0x88);
+ break;
+ case BPF_H:
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89);
+ else
+ EMIT2(0x66, 0x89);
+ break;
+ case BPF_W:
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
+ else
+ EMIT1(0x89);
+ break;
+ case BPF_DW:
+ EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
+ break;
+ }
+ if (is_imm8(off))
+ EMIT2(add_2reg(0x40, dst_reg, src_reg), off);
+ else
+ EMIT1_off32(add_2reg(0x80, dst_reg, src_reg), off);
+ *pprog = prog;
+}
+
+static int emit_call(u8 **pprog, void *func, void *ip)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+ s64 offset;
+
+ offset = func - (ip + X86_CALL_SIZE);
+ if (!is_simm32(offset)) {
+ pr_err("Target call %p is out of range\n", func);
+ return -EINVAL;
+ }
+ EMIT1_off32(0xE8, offset);
+ *pprog = prog;
+ return 0;
+}
static bool ex_handler_bpf(const struct exception_table_entry *x,
struct pt_regs *regs, int trapnr,
@@ -773,68 +868,22 @@ st: if (is_imm8(insn->off))
/* STX: *(u8*)(dst_reg + off) = src_reg */
case BPF_STX | BPF_MEM | BPF_B:
- /* Emit 'mov byte ptr [rax + off], al' */
- if (is_ereg(dst_reg) || is_ereg(src_reg) ||
- /* We have to add extra byte for x86 SIL, DIL regs */
- src_reg == BPF_REG_1 || src_reg == BPF_REG_2)
- EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
- else
- EMIT1(0x88);
- goto stx;
case BPF_STX | BPF_MEM | BPF_H:
- if (is_ereg(dst_reg) || is_ereg(src_reg))
- EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89);
- else
- EMIT2(0x66, 0x89);
- goto stx;
case BPF_STX | BPF_MEM | BPF_W:
- if (is_ereg(dst_reg) || is_ereg(src_reg))
- EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
- else
- EMIT1(0x89);
- goto stx;
case BPF_STX | BPF_MEM | BPF_DW:
- EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
-stx: if (is_imm8(insn->off))
- EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
- else
- EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
- insn->off);
+ emit_stx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off);
break;
/* LDX: dst_reg = *(u8*)(src_reg + off) */
case BPF_LDX | BPF_MEM | BPF_B:
case BPF_LDX | BPF_PROBE_MEM | BPF_B:
- /* Emit 'movzx rax, byte ptr [rax + off]' */
- EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
- goto ldx;
case BPF_LDX | BPF_MEM | BPF_H:
case BPF_LDX | BPF_PROBE_MEM | BPF_H:
- /* Emit 'movzx rax, word ptr [rax + off]' */
- EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
- goto ldx;
case BPF_LDX | BPF_MEM | BPF_W:
case BPF_LDX | BPF_PROBE_MEM | BPF_W:
- /* Emit 'mov eax, dword ptr [rax+0x14]' */
- if (is_ereg(dst_reg) || is_ereg(src_reg))
- EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
- else
- EMIT1(0x8B);
- goto ldx;
case BPF_LDX | BPF_MEM | BPF_DW:
case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
- /* Emit 'mov rax, qword ptr [rax+0x14]' */
- EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
-ldx: /*
- * If insn->off == 0 we can save one extra byte, but
- * special case of x86 R13 which always needs an offset
- * is not worth the hassle
- */
- if (is_imm8(insn->off))
- EMIT2(add_2reg(0x40, src_reg, dst_reg), insn->off);
- else
- EMIT1_off32(add_2reg(0x80, src_reg, dst_reg),
- insn->off);
+ emit_ldx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off);
if (BPF_MODE(insn->code) == BPF_PROBE_MEM) {
struct exception_table_entry *ex;
u8 *_insn = image + proglen;
@@ -899,13 +948,8 @@ xadd: if (is_imm8(insn->off))
/* call */
case BPF_JMP | BPF_CALL:
func = (u8 *) __bpf_call_base + imm32;
- jmp_offset = func - (image + addrs[i]);
- if (!imm32 || !is_simm32(jmp_offset)) {
- pr_err("unsupported BPF func %d addr %p image %p\n",
- imm32, func, image);
+ if (!imm32 || emit_call(&prog, func, image + addrs[i - 1]))
return -EINVAL;
- }
- EMIT1_off32(0xE8, jmp_offset);
break;
case BPF_JMP | BPF_TAIL_CALL:
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